Method and apparatus for establishing and sharing a virtual change notification list among a plurality of peer nodes

In a data router, a virtual output queue system for propagating route change notifications to individual ones of a finite set of peer routers, the system comprising:

• a virtual output queue (VOQ);
• a facility for entering and deleting change notifications as event objects in the VOQ;
• and
• an access module for managing access to the queue on behalf of individual ones of the finite set of peer routers, the access module retrieving event objects from the queue and sending the event objects to the router for which access is made.

A method for propagating event objects to a finite set of consumers, comprising the steps of:

• (a) placing the event objects one-at-a-time in a first-in-first-out queue;
• (b) associating a number with each specific event object in the list, the number indicating the number of consumers in the set currently accessing the specific event object;
• and
• (c) decrementing the number associated in step (b) with each event object by one each time a consumer finishes access to that event object, such that, when the number is zero for an event object, and the event object is at the head of the queue, that object has been accessed for all consumers requiring access, and may be removed from the queue.

A method for propagating route changes to a finite set of peer routers, comprising the steps of:

• (a) placing the route changes as event objects one-at-a-time in a first-in-first-out queue;
• (b) associating a number with each specific event object in the queue, the number indicating the number of peers in the set currently accessing the specific event object;
• and
• (c) decrementing the number associated in step (b) with each event object by one each time a peer finishes access to that event object, such that, when the number is zero for an event object, and the event object is at the head of the queue, that object has been accessed for all peers requiring access, and may be removed from the queue.

In a multiple-processor data router, a virtual output queue system for propagating route change notifications to individual ones of a finite set of processor-controlled nodes within the router, the system comprising:

• a virtual output queue (VOQ);
• a facility for entering and deleting change notifications as event objects in the VOQ;
• and
• an access module for managing access to the queue on behalf of individual ones of the finite set of nodes within the router, the access module retrieving event objects from the queue and sending the event objects to the node for which access is made.

A method for propagating route changes to a finite set of processor-controlled peer nodes in a multiple-processor router, comprising the steps of:

• (a) placing the route changes as event objects one-at-a-time in a first-in-first-out queue;
• (b) associating a number with each specific event object in the queue, the number indicating the number of nodes in the set currently accessing the specific event object;
• and
• (c) decrementing the number associated in step (b) with each event object by one each time a node finishes access to that event object, such that, when the number is zero for an event object, and the event object is at the head of the queue, that object has been accessed for all nodes requiring access, and may be removed from the queue.